Abstract:

n-Hexane evaporation residue refers to the total amount of chemical potentially released when an analog sample is
in contact with oil. According to the Chinese national standard GB 4806.1—1994 Food Hygiene Standards Rubber Products,
two analytical methods, area and mass methods were used to analyze the uncertainty in the determination of n-hexane
evaporation residues of silicone rubber seals in pressure cookers and establish an appropriate mathematical model. By
analyzing the various sources of uncertainty and calculating the uncertainty components, the amount of n-hexane evaporation
residue of silicone rubber seals was 375.8 mg/L with relative standard uncertainty of 4.138 8 mg/L and expanded uncertainty
of 8.267 6 mg/L (k = 2) when the mass method was used, while the amount of n-hexane evaporation residue of silicone
rubber seals was 497.15 mg/L with relative standard uncertainty of 6.164 7 mg/L and expansion uncertainty of 12.329 4 mg/L
(k = 2) when the area method was used. In conclusion, the area method is closer to practical applications and helpful for
enterprises to conduct internal quality control. Therefore, we recommend that the area method should be applied with priority
to test n-hexane evaporation residues of silicone rubber seals.

Key words: silicone rubber seals, n-hexane evaporation residue amount, uncertainty